Fluorescence observation is used in many technical, biological or medical applications in order to visualize various objects such that different types of structures within the object can be distinguished from each other. For this purpose, an illumination light filter is disposed in a beam path between a light source and the object to be observed, and an observation light filter is disposed in a beam path between the object and an eye or a camera detecting images of the object. The illumination light filter allows light to traverse the filter, which excites a fluorescence within the object. The observation light filter allows fluorescent light from the object to traverse the filter. The observation light filter is further configured such that it does not allow light to traverse the filter having wavelengths coinciding with wavelengths of the fluorescent light, which are allowed to traverse the observation light filter. Thus, the light allowed to traverse the observation light filter is substantially only fluorescent light other than illumination light, which has been reflected from or scattered at the object. For this purpose, the illumination light filter blocks substantial portions of the spectrum such that, when the light source is a white light source, the light incident on the object and having traversed the illumination light filter does not allow for an unbiased natural color impression of the object and of, in particular, white regions within the object.
In some situations, the object includes fluorescent regions and non-fluorescent regions, wherein it is desirable to both visualize the fluorescent regions and to allow to perceive the non-fluorescent regions with a substantially natural unbiased or unaltered color impression.